Question

Megan is performing an experiment in her biology lab. She drops a glass pipette full of an unknown substance on the ground. The pipette breaks and the substance spills on the floor. What should Megan do immediately after she drops the pipette?

Answer 1

I would say that she should immediately alert everyone in the building so that people can vacate the immediate vicinity. Subsequently, once the content of the pipette is established, the appropriate and safe clean-up procedure can be initiated.  

Answer 2

First, he should inform all the people who might be in the building to quit immediately.

Since the content which was in the pipette is not known they vacate and let the investigation to be carried out.
If the content is known, then the procedure on how to lean up the mess is carried out. After that people can go back to their normal duties.