Interestingly, it turns out the gel is really 5% Hydroxyethylcellulose and 95% water, which is in the same family as Methylcellulose, which is more commonly used here.
I can imagine a scene where an intern assistant nurse wearing scrubs is told to apply ultrasound gel. This is her first time on her first day. She doesn't know she is only supposed to use a couple squirts. Instead, the nurse covers the patient's nude body from head to toe in 5 liters of the gel while making a mess all over her scrubs.