この部屋では走るな。

this (something or someone close to the speaker (including the speaker), or ideas expressed by the speaker)

room; apartment; flat; pad; chamber; stable

indicates location of action; at; in; indicates time of action; indicates means of action; cause of effect; by; and then; so; indicates continuing action; indicates certainty, emphasis, etc.

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to run; to travel (movement of vehicles); to drive; to hurry to; to retreat (from battle); to take flight; to run away from home; to elope; to tend heavily toward

(sentence end, mainly masc.) indicates emotion or emphasis; (used with masu stem verb) command; (used with dictionary form verb) prohibition