When you move in a laboratorium you have to treat everything as if it was dangerous. Therefore:
Anyway if anything breaks leave it. As a main rule inform in stead one of the laboratories' own staff. The broken, how inconsiderable it might looks, it can be dangerous or be a result of many days work. A knowledgeable person maybe can save some - but on the other hand, if you start to collect everything there is a chance that everything will be lost.
If a bottle breaks and the content runs out, you have to leave the laboratory immediately. You are NOT allowed to start wiping it up, because the content can be corrosive or toxic. AND if you get anything on you, then after leaving the laboratory, flush it with a lot of water. Afterwards, contact a knowledgeable person, who can decide what to do further.
If you observe anything which seems strange and makes you feel insecure, for instance strange smells, sounds or smoke - you have to immediately leave the room and contact a knowledgeable person, who can decide if it is dangerous or not. Remember that the working environment representative is there for you and they have to solve problems for you.
It is better to ask one time too often, than to avoid asking!!
Remember by accidents:
Don't touch anything, but leave the room
Flush with a lot of water, if you got anything on you
Contact the laboratory staff
The employer must secure that employees from non-AU companies, who perform work for the company, will get a appropriate instruction about safety and health conditions related to their work (§20 in the Danish Working Environment Service declaration from 17 June 2004 about work performance).
Thus, the Department of Chemistry is obliged to give external workmen instructions, so that they can work and walk around at Department of Chemistry obliging to rules and regulations. This duty is a supplement to the normal duty to instruct own employees for a completely correct work process.
Department of Chemistry has to inform about contact persons in the building with name and phone number.
When working in the buildings of Department of Chemistry, workmen will often disturb the Department's other employees. To the internal employees it does not matter if a workman comes from a external company or from "Teknisk Forvaltning" - they are all to be considered strangers and the issues are the same: Insufficient info, annoyment and/or problems. Be aware that even extremely short leaks or breach in electricity or water supply can have extreme consequences.