There is – enclose a Pbindef statement in parentheses that are on their own lines. This marks a group of lines as a “region” which can then execute as a block, if the cursor is anywhere inside the region when you hit Ctrl-enter.
That is – starting with the cursor on an empty line, type a left-paren and hit return. Then write your Pbindef, with as many lines as you need. Then, with the cursor on the empty line after your full Pbindef, type a right-paren.
Spaces vs returns are not important for SC language syntax. The issue here is that the editor needs to know which part of the text to send to the interpreter. If you do nothing about that, it will assume a single line (which is why you had problems with line breaks). You can manually select a multiline block, but I imagine that could be tricky with screen readers. The parenthesized region approach is, I think, a good habit to get into.
(Note, though, that some types of syntax error in the document that appear before a parenthesized region can cause the later region not to be recognized.)