Both events in your sentence take place in the past and the application of 〜たら and 〜と is slightly different.
As Yang Muye says, と is often used in stories to objectively describe events and the conjunctive すると is often used to set up the scene for what happens next. Momotaro, the peach boy is sometimes given as an example of this use of と.
〜たら on the other hand cannot be used if the actor has control over the sequence of events which is the case here.
This use of と is different from the "conditional-と" which is used to mark a condition that brings about an uncontrollable event. In such cases S2 cannot be volitional and the following sentence (not set in the past) is ungrammatical:
Objectively is the operative word in all this. The following sentence is incorrect because the writer is too closely involved in the events:
The て-form is more natural:
And the following sentence is acceptable because even though the writer is describing his own activities, he has distanced himself from them:
Reference: A students' guide to Jpse Grammar by Naomi Hanaoka McGloin