Not sure. I work at a coffee shop as well, and even in my small area if I were to make a mess like this it would probably take at least 10 minutes to clean milk off the floor, walls, fridges, the counter, etc. Especially if OP was working a morning rush (or any rush) waiting customers would be getting upset and there would be an incredible line of drinks waiting for OP to make after they clean up. Usually when we make messes at my store we just have to keep going and worry later.

Slipping on a wet floor whilst carrying hot drinks doesn't sounds like a good work environment to me.

Lines at coffee shops don't always move slow and customers can be mean for even the smallest thing. If it's a rush, it can be even worse. An example of how mean people can be: My store is a drive thru store and an evenings store so we can get really, really busy. One night, the line at drive was super long and wait times were high but we were all doing our very best to get drinks done and out and keep times as low as possible but someone had called off. Most customers were understanding except for two people. One guy I interacted with directly. He ordered his drinks and, when I asked if he wanted anything else, he said "I may as well as order a sausage and cheddar breakfast sandwich since I've been waiting so long." When he got to the window, he continued to complain and, when I asked how his night was, he only said "Well, I would've liked to be home 20 minutes ago!" And his parting line as he drove off? "You guys need help!" Also, it's no surprise that sometimes we have high wait times on drive - we're the only drive thru location in my County. The second person who had an issue was someone who I heard about through my co-worker cause it happened while I was on break. We had one of our new hires on bar and the lady at the window - who was complaining about the wait time - told my coworker we'd be "better off without the dead weight on bar." My coworker that he's new and still learning but the customer only said "doesn't matter. He shouldn't be on bar!" And, yes, it was loud enough for him to hear. Bonus story: Two different sets of customers in one night. One was at the drive thru and, after that experience, where they told my coworker (a different one. she was hired this year but has been with us for several months already) to "**** off!" They took her off window and put her on bar and three clovers came in. Well, she tried to be efficient and measured out the beans for three instead of one but then realized she couldn't make three at once on the clover machine and the group for the clovers were watching her and, after seeing this, asked her "Are you retarded?!" After both of these combined in just a few short minutes, my shift lead gave her her last ten early so she could compose herself and take some time to collect herself but she cried on her break. So, yeah, most customers are nice and understanding but some can be real jerks. In OP's case, there should've been someone who can take over bar for a moment so they could clean themselves up but it seems like that wasn't possible right now. And someone else can help clean up the mess the best they can while OP makes drinks.