Can trou aux cerfs erupt?

Why nobody is alarmed and not doing anything as it could erupt any moment

Trou aux cerfs is a dormant volcano which means that it can erupt at any time. Recently, it has been noted that there has been a decrease in the normal pH of the Mauritian waters; this phenomenon has been associated to some probable activity related to the Mauritian volcanoes.

If it erupts we have the Candos Hill which can be used as a stopper .

Mauritius is a crater in itself and trou cerfs is just a small carter formed within the big crater which you can identify by joining all the mountain ranges.

Definitely. no volcano is ever really 'dormant', its just a term used if it did not erupt for a long time!