Timing is everything. Only a few seconds later, a shrill voice could be heard echoing down the hallway - a voice that was, perhaps, all too familiar. And one most certainly not one the group in Medbay would want to hear right now.

"MEMBERS OF THE CREW HAVE BEEN SPOTTED HEADING IN THIS DIRECTION. FIND THEM."

A second voice, only slightly different sounding than the first, replied. "I OBEY."

While they sound of them moving off was too far away to be heard, given their location, it's likely only a matter of time before either or both Daleks come across their position. Waiting for them to pass and slipping out might not work here.