Does anyone have some tips for using RNAprotect for cells grown in a monolayer or something similar?

The manual of RNAprotect Cell Reagent only mentions using RNAprotect with a solution or pellet of cells.

Normally I would remove our cells (HOK-18A) from their support with RLT buffer (RNeasy kit; QIAGEN) and then transfer them to an epp, after which I could add the RNAprotect. If I'm running a lot of samples, it'll take a while before I get to the last sample, influencing the RNA quality. To ensure a more consistent RNA quality between the first and last sample I would like to add RNAprotect before removing the cells from their support.

Thanks!