break open vs burst out

break open and burst out both are verbs.

Word	Noun	Adjective	Verb	Adverb
break open	No	No	Yes	No
burst out	No	No	Yes	No

As verbs, break open and burst out are synonyms defined as:

Other synonyms of break open include erupt, flare, flare up, irrupt.

break open (verb)	burst out (verb)
erupt or intensify suddenly	erupt or intensify suddenly
come open suddenly and violently, as if from internal pressure	give sudden release to an expression
open with force	appear suddenly or unexpectedly; happen unexpectedly